Income Taxes - Rollforward of Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits - Beginning Balance	$ 148	$ 143	$ 125
Change to positions that only affect timing	(57)	(1)	13
Increases based on tax positions related to current year	3	3	4
Increases based on tax positions prior to current year	1	3	4
Decreases based on tax positions prior to current year	(1)	0	(3)
Unrecognized tax benefits - Ending Balance	94	148	143
Income taxes receivable, noncurrent	31	50
Pepco Holdings LLC
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits - Beginning Balance	59	56	52
Change to positions that only affect timing	(9)	1	3
Increases based on tax positions related to current year	1	2	1
Increases based on tax positions prior to current year	0	0	0
Decreases based on tax positions prior to current year	0	0	0
Unrecognized tax benefits - Ending Balance	51	59	56
Atlantic City Electric Company
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits - Beginning Balance	17	16	15
Change to positions that only affect timing	(2)	1	1
Increases based on tax positions related to current year	0	0	0
Increases based on tax positions prior to current year	0	0	0
Decreases based on tax positions prior to current year	0	0	0
Unrecognized tax benefits - Ending Balance	$ 15	$ 17	$ 16